A Mequon farmer says his corn is growing well ahead of the Fourth of July, clearing hip-high, even as Wisconsin endures its biggest heat wave of the season, with high temperatures topping 90 degrees all week.Bud Schmit, who has spent more than 50 years raising vegetables on his Mequon farm, said the old benchmark of "knee high by the Fourth of July" no longer captures what healthy corn looks like in a modern growing season."I'm very pleased with…